The Impact of Yamal on the Spaghetti Graph

We’ve been discussing Briffa and Yamal at CA for a couple of years and many, if not most, regular readers understand the significance of the Yamal collapse. For example, as recently as Sept 19, we were observing the dependence of the Kaufman reconstruction on the Yamal series. So the long-sought fresh information on Yamal (and I’ve been aware of that the Yamal data had been finally placed online for only a few days) fell on fertile soil here.

Some commentators have been very quick to seize on one more example of perceived Team iniquity. That I had been publicly seeking this data for a long time and that Briffa had withheld the data not just from me (but also from D’Arrigo et al, for example) lent an unsavory aspect to CRU’s conduct, fresh after widespread unfavorable publicity for CRU’s withholding of temperature data (by Briffa’s long-time colleague and mentor, Phil Jones.)

Between these two camps, there are obviously readers who wish to understand the implications, if any, of the Yamal problems, without being particularly interested in the sordid backstory of past obstruction. I’ll try to provide some notes on this today. These are not comprehensive, but introductory.

IPCC AR4 said that the late 20th century was the warmest in 1300 years, relying not just on the Mann Hockey Stick, but on about 10 reconstructions by a relatively small group of authors (the “Hockey Team” or the “Team”). These reconstructions are typically presented in a smoothed version as what I’ve called here “spaghetti graph” – a term that has spread into wider usage. The IPCC AR4 spaghetti graph is shown below. Wikipedia has a similar spaghetti graph; the NAS Panel had a simplified spaghetti graph. In detail, these reconstructions seem to agree on very little other than that the modern warm period is slightly warmer than the Medieval Warm Period.

The IPCC spaghetti graph contains 10 “multiproxy” reconstructions, 9 of which go back to the MWP. These will be discussed below. It also contains a short reconstruction from boreholes and a short reconstruction from glacier advance and recession, neither of which pertains to the medieval-modern differential and will not be discussed here.

You will frequently see apologists state that these reconstructions provide “independent” evidence. However, this is not the case on two counts. The same proxies are used over and over again – a point reported at CA on many occasions and confirmed in Wegman et al 2006. Thus, if problems arise with (say) bristlecones or (say) Yamal, this will affect multiple studies and not be contained to one result. More on this below. In addition, there are not really 10 “independent” groups, as “independence” is understood in the real world. Mann and Jones 2003 is not independent of Mann, Bradley and Hughes (1998) or Jones (Briffa) et al 1998 or Rutherford et al 2005 (Mann, Osborn, Bradley, Briffa, Hughes and Jones).

The other point – which I will state here but not prove – is a point about reconstruction methodologies. It is well known in the statistical climate blogs (CA, Jeff Id, David Stockwell, Lubos) that typical paleoclimate operations applied to red noise will yield HS patterns – a line of argument that Ross and I discussed in detail in connection with MBH PC methods, but the same problem arises when you cherry pick from red noise or do ex post correlation weighting. To my knowledge, the climate “community” is in denial on this issue. There is a corollary to this “theorem” – a point that we discussed in our Reply to von Storch and Zorita, which is very important, but which hasn’t got as much attention. If you manually include a huge HS-shaped series in a bunch of red noise and apply standard paleoclimate methods to the network – CPS, as well as Mannian PCs – you get an enhanced HS back with a a minor amount of static.

Rather than paleoclimate methods being “robust” as they self-proclaim, they are profoundly non-robust as this term is used in statistics – denoting the lack of stability of results to individual series. There are two series that play a particular role in the current spaghetti graph population: strip-bark bristlecones/foxtails (especially as Mann’s PC1) and Briffa’s Yamal (and its predecessor). These two series are both shown in IPCC AR4 Box 6.4 Figure 1 as the two biggest HS series – going off the top right corner of the graphic.

Box 6.4, Figure 1. The heterogeneous nature of climate during the ‘Medieval Warm Period’ is illustrated by the wide spread of values exhibited by the individual records that have been used to reconstruct NH mean temperature. These consist of individual, or small regional averages of, proxy records collated from those used by Mann and Jones (2003), Esper et al. (2002) and Luckman and Wilson (2005), but exclude shorter series or those with no evidence of sensitivity to local temperature. These records have not been calibrated here, but each has been smoothed with a 20-year filter and scaled to have zero mean and unit standard deviation over the period 1001 to 1980.

One important “family” of spaghetti graph reconstructions are highly dependent on strip bark bristlecones/foxtails (a topic which has been much discussed here and elsewhere) but which do not use Yamal. These are “highly dependent” on strip bark bristlecones/foxtails in the sense that their methods do not yield a HS without them. Examples include MBH98-99, Crowley and Lowery 2000, Esper et al 2002 plus the re-statements of the NBH network in Rutherford et al 2005, Mann et al 2007 and Wahl and Ammann 2007.

A second “family” of spaghetti graph reconstructions are dependent on Briffa’s Yamal – again, in the sense, that the equivalent calculation using plausible alternatives (e.g. Esper’s Polar Urals version instead of Briffa’s Yamal) yield different MWP-modern relationships. Examples include Briffa 2000, the closely related D’Arrigo et al 2006 and very recently, Kaufman et al 2009 (despite its first impression of a very different network.)

A third “family” of reconstructions wears both belt and braces – i.e. using both strip bark and Yamal. Key examples are Mann and Jones 2003, Mann et al (EOS 2003), Osborn and Briffa 2006, Hegerl et al 2007. The recent UNEP graphic uses the Mann and Jones 2003 version. A common stratagem in these studies is a leave one out sensitivity – where they show that they can “get” a similar result by leaving out any individual proxy. They can do so safely because they have both Yamal and bristlecones.

There are a couple that are a bit sui generis, but these unfailingly have some serious problem.

Jones et al 1998 uses neither Yamal nor bristlecones, but still has a slight modern-medieval differential. In its early portion, it uses only three series, two of which are early Briffa series (Tornetrask and Polar Urals pre-update). Both these series have serious problems – Briffa’s original Tornetrask series contains a gross manual adjustment to increase the 20th century relative to the MWP. See early CA posts on this.

Moberg uses both bristlecones and Yamal, but I view it as sui generis as well. Moberg used some unorthodox wavelet methods, that I’ve sort of emulated, but gave up trying to do so precisely. However, I can confirm that the bristlecone versions used in Moberg are not Graybill versions and don’t affect the result; they are merely fill. I’m not sure what impact Moberg’s filtering method will have on Yamal – I’ve not analyzed that in detail, but may do so some day. I’ve discussed Moberg problems in the past and, for present purposes, merely note that it is not a safe haven, but that it does not appear to stand or fall with Yamal and thus is not discussed further today.

And because of the non-robust methods used in these studies, replacing the Briffa Yamal version with a more defensible alternative (such as Esper Polar Urals either individually or in combination with the subfossil Yamal data and Schweingruber russ035w in Yamal) is going to have a material impact on the medieval-modern differential.

Steve, excellent article. Is there a way to access some of the plotted data you have shown in a text or EXCEL file format? I would like to compare it to the analysis I did using the long term European temperatures from Rimfrost.

What I find interesting is that the graph shows a clear MWP around 1000 AD. And if you compare chalk with chalk, i.e. just look at the proxies, the MWP is just as warm as the late 20th century, contradicting the IPCC’s own claim (see my page on this).

Steve, summary/overview posts like this are really helpful, please can we have more!

Somehow, this work needs to be installed into the establishment literature. Is there any prospect that a paper could be written that would get past the “peer reviewers” of the journals that seem to dominate political thinking on climate affairs? I know that I could not help in any way. If I could I would! The only feasible contribution would be by reading a draft copy and providing what I hope would be an impartial commentary.

It is quite mind-boggling in its implications, something that is certain to have been noticed by “The Team”, who have so far as I can tell been keeping their counsel up to now.

Would there be any point in making direct contact with politicians? OK, we know that they don’t understand any of this from a scientific viewpoint, but a careful drip-feed of the essence of Steve’s unearthing of data that have hitherto been kept from public scrutiny might just have an effect. I have been in contact with my Member of Parliament regarding the FoI debacle regarding “classified” climate time series that Phil Jones has convinced our MOD would be harmful if released to the general public. My request was refused with virtually identical wording to those of others who contribute to CA, and my MP appeared to be intending to take the matter further. I hope so.

Thanks, Steve, for that brief overview of the spaghetti graphs and the series contained within. That was great.

I would love to see the equivalent of a social network chart or map that illustrates the dependencies. Maybe something similar to the chart in Wegman’s report on MBH? This would make it even easier to identify how these things are interconnected.

In the Yamal case, 12 trees created the key hockystick-ness. In the case of Bristlecone pines, I believe there were about 22 trees (anyone remember?). So most of the key result in the spagetti graphs is coming from about 30-35 trees. A few good men indeed.

It would seem to be worthwhile to add a paragraph discussing the divergence issue of the Greybill & Ababneh data.

That is: The last several posts are pretty good at highlighting “There are reasons to believe there are problems in Yamal.” You’ve made reference above to how strongly the other reconstructions rely on the bristlecones and foxtails – but a short mention of the results Ababneh got rely deserves a slot in here. We’re discussing divergence – and that surely is some.

Eric, if I understand your question correctly, neither of the two cited studies you mention w/stand “prima facie” scrutiny in light of the sui generis problems mentioned briefly in Mr. McIntyre’s post. These two remaining “hockey sticks”, while not subject to the post’s main thrust, contain either obvious procedural issues and/or utilize questionable analytical “tools” not generally used or accepted w/in the general scientific community that in turn color their respective conclusions. Thus, the AGW crowd’s primary intellectual foundation lies on life support barring some convincing rebuttal (which I believe they lack). In summation, Mr. McIntyre’s determination to independently validate these many studies predicting future “runaway” temperature increases, has itself lead to the most reasonable and logical explanation for these studies’ disturbing predictions – “operator” error.

Steve: I’ve written posts on whether the Hockey Stick “matters” in the big picture and do not hold the same view as the one that you espouse here. Indeed, when people say to me: if the Stick is wrong, then the situation is much worse than we think and my answer is always: then we should know if it’s wrong and govern ourselves accordingly and give no thanks to those people whose obstruction have delayed our becoming fully appraised of the situation. This is a different moral entirely. I don’t want to debate this position at this time as I’m very busy on practical analyses.

In the Yamal case, 12 trees created the key hockystick-ness. In the case of Bristlecone pines, I believe there were about 22 trees (anyone remember?). So most of the key result in the spagetti graphs is coming from about 30-35 trees. A few good men indeed.

Did someone answer your question? Is the HS based on a total of 34 trees?

Do I understand correctly that baring some serious and unforeseen defense of Yamal and Bistlecone pine proxies only two “hockey sticks” still stand to show that warming in our time is unprecedented, Jones et all 1998 and Moberg, and there are other concerns about these?

I have just checked the page where the raw data is, and it’s interesting to see the timestamps involved with the different objects on the page. It seems to have happened happened on Sep, 8th. But what intrigues me Steve is the TayBavRing.raw file; it also seems to be new. Might it also represent something special?

It seems there are a whole teams worth of hockey sticks on the fire. I don’t have familiarity will all of these papers, but I’ve read some.

There is a corollary to this “theorem” – a point that we discussed in our Reply to von Storch and Zorita, which is very important, but which hasn’t got as much attention. If you manually include a huge HS-shaped series in a bunch of red noise and apply standard paleoclimate methods to the network – CPS, as well as Mannian PCs – you get an enhanced HS back with a a minor amount of static.

If I might, I did a post a while ago which got very little attention at the time that demonstrates exactly the effect referred to at least for CPS.

While I’ve hung on with little more than best guesses, hunches when to skip, and fragments of understanding, I now feel I’m meeting you head on, relishing your story, grasping all the details, and seeing why one had to just hang on and slog on through the swamp.

Now this Hockey Stick hydra has three heads: Yamal, bristlecones, and CRU undisclosed records. My recent forays into the nearest reliable Arctic thermometer records from GISS and John Daly (at Jeff Id) all show thermometer records without any sign of the crucial sharp Hockey Stick upturn. I cannot believe CRU can show anything very different.
Steve: The Arctic temperature record issues are entirely different and, as I’ve said before, I would like to keep such discussions entirely separate.

As Steve notes in his post there is a lot of history here. I wish that google worked better on searching CA or that I was smarter. Anyways, I was searching away looking for the first time I ever used the term “treemometer” ( oct 13, 2007) and during my wanderings I ran across a 2006 thread discussing Yamal. Now, this was back in the day when Dendro’s showed up here. back in the day when Steve Sadlov roamed the threads. Old school CA. It’s pretty funny kim is there and hasnt changed one bit. And guess what Rob Wilson showed up.. and complained about not being able to get Briffa’s data.

I’m not going to post the link. I worked hard to find this and you can core your own damn trees.

If bender asks nice, I will. Otherwise go read some old posts on Yamal before you open your cherry pie hole

Re: theduke (#22), this is a Telegraph hosted blog, not part of the main newspaper. But given that Richard North at the EU Referendum blog has also picked up on it you can probably assume it will feature in Christopher Booker’s column next Sunday.

Ok, for grins. Rob Wilson also wanted the Yamal data. Thanks to steve he now can get it. Isn’t it a bit odd when one dendro hides data from another? Hmm. I wonder if Briffa had a confidential agreement with russian lumberjacks about revealing this proprietary ring data?

Looking at this in broad daylight, I have to say that I am astonished.
It is evident that you need the strongest possible justification for the data manipulation that was undertaken, and looking at the result of the data manipulation, it seems that it couldn’t be possible to justify such a manipulation under any circumstances.

I too must have missed the section in the “How to do Science like real Scientists” book where scientists have the authority to alter the data to what they think it should be and then write it all up with statistical metrics as if nothing had gone on.

Well in Canada here is the response of the Canadian Press to my complaint about the Bob Weber account of Kaufman et al. 2009 in the Globe and Mail and the new developments:
September 29, 2009
“Dear Mr. San:

Thank you for your continued interest in our coverage of an important public issue. Before I address the substance of your complaint, allow me to point out that Bob Weber’s job as a reporter is to fairly reflect the nature and conclusions of the research. He did that in this case and so, with respect, I submit that your charge of bias is unwarranted.

Your main concern is with the conclusions of the scientist whose work is described. In rebuttal, you draw on the writing of Steve McIntyre, a one-time stock analyst who I believe has never been published in a peer-reviewed journal. His previous attacks on the “hockey-stick” theory have been examined and did not result in substantial changes to it. As we understand it, you agree with McIntyre’s contention that proxies used in this particular climate reconstruction have been pre-selected or weighted to give a conclusion that agrees with climate orthodoxy. The Kaufman paper, while based on previous research, did not simply regurgitate older data sets. The data used were significantly deeper both in regard to time (2,000 years) and space (the entire circumpolar world). Its conclusions were widely reported and accepted by major science journalists around the world.

It is not our intention to debate the truth of climate change with you. The Canadian Press, like most reputable news organizations, seeks to accurately report scientific findings that have been judged legitimate by experts in the field. When peer-reviewed science appears that questions current models, we will report on it. In fact, Bob Weber has done exactly that in the past.”

Since your concerns seem to have more to do with the article’s subject matter than with the accuracy of the reporting, we will respectfully consider this matter closed.

HEATHER BOYD
Prairies Bureau Chief”

My Complaint letter to them:

“As a follow up to my initial complaint about the biased tone of Mr Bob Weber story related to the Kaufman et al. 2009 “Arctic Warmer than it has ever been for the past 1,000years” that appeared in the Globe and Mail: A new development has happened thanks to the sleuth work by Steve McIntyre at climateaudit showing that there is a divergence between the full data and the Briffa data archived at CRU used by Kaufman et al. 2009. The late 20th century warming recorded is only shown on selected after the fact data while the entire dataset shows no “unprecedented warming”, in fact shows slight cooling. http://www.climateaudit.org/?p=7229 The demonstration links are below: “Combining the CRU and Schweingruber data yields the green line in the 3rd figure above. While it doesn’t go down at the end, neither does it go up, and it yields a medieval era warmer than the present, on the standard interpretation. Thus the key ingredient in the 10 following studies that have been invoked to support the Hockey Stick, namely the Briffa Yamal series (red line above) depends on the influence of a thin subsample of post-1990 chronologies and the exclusion of the (much larger) collection of readily-available Schweingruber data for the same area: Briffa 2000, Mann and Jones 2003; Bradley, Hughes and Diaz 2003; Jones and Mann 2004; Moberg et al 2005; D’Arrigo et al 2006; Osborn and Briffa 2006; Hegerl et al 2007; Briffa et al 2008; Kaufman et al 2009.” All these papers were peer-reviewed and published in prestigious scientific journals… The latest debunk by Steve MacIntyre at climateaudit invalidates the so called “unprecedented” XX century warming shown through dendrochronology proxies (tree rings studies). This includes the Kaufman et al 2009, about the “Arctic being the warmest in the past 1,000 years” reported in the Globe and Mail by Mr. Weber of the Canadian Press… http://www.climateaudit.org/?p=7168 The AGW proofs are melting fast too… Perhaps the Canadian Press should pay attention to the great work being done in this country!”
=================
September 8, 2009

“Dear Mr. San.

Thank you for contacting The Canadian Press to express your concerns about Bob Weber’s story on climate change in the Arctic.

I apologize for the delay in responding to your messages.

We have discussed your concerns with Bob Weber. We’re not in a position to say whether Kaufman’s previous work was “flawed,” and I note that you do not provide evidence to support your contention. Even if you had, we believe that even if Kaufman et al had published flawed studies in the past, that wouldn’t necessarily affect the current paper, which was peer-reviewed and published in a highly prestigious journal.

Bob Weber did ask Kaufman about the reliability of the proxies (i.e., tree rings and sediment data used to suggest temperature) and was told they are standard scientific tools that have been in wide use for many years. He also said the protocols for their use have been established by experimental means. In other words, tree rings and sediments have been compared to years for which actual temperature records exist and the relationships between codified empirically. Those relationships are then used to suggest temperatures in times and places for which no records exist.

You also infer that in coming up with a hockey-stick graph, Kaufman simply “rehashes” previous IPCC studies, drawing data from them. Kaufman collected his own data, analyzed it, graphed it and then compared it with the IPCC’s hockey stick.

We have taken your concerns so seriously that Weber looked carefully at the climate blog to which you refer and he could find little evidence that Kaufman distorted his findings to conform to scientific orthodoxy. The blogger teases out specific components of Kaufman’s data set and demonstrates that focusing on them yields different results, but surely that is not a surprise. One of the points of Kaufman’s research is that it averages different data sources to account for the biases in each.

After a careful review of all of your concerns, we stand behind our story.

Best regards,

HEATHER BOYD
Prairies Bureau Chief”

My complaint then:
Despite my initial complaint 24 hours ago, the story by Bob Weber has not been altered to reflect the reality of the science behind the Kaufman et al. Science 2009 paper described in his article. If this serves as an example of the Canadian Press ethics, what credit can be attributed to reports issued from your institution on domain where my knowledge doesn’t allow me to point out the bias? “The Bob Weber The Canadian Press Last updated on Thursday, Sep. 03, 2009 05:11PM EDT A groundbreaking study that traces Arctic temperatures further back than ever before has shown the region is now warmer than at any time in the past 2,000 years… is truly an incomplete description of the state of scientific knowledge in this field. In particular it completely fails to check the co-authors past history of flawed studies, the validity of the proxies and take the PR from Science and the lead author at face value, despite the existence of a significant amount of peer reviewed literature demonstrating the flaws in the previous studies by IPCC co-authors, rehashed in the Kaufman et al. 2009 paper. A scientific case is built at http://www.climateaudit.org/?p=6932 where Mr. Weber could find all the information he needs to amend his article and transform a piece of propaganda into a piece of information.”

Thank you for this introductory outline of the *implications* of the many proxy problems. For those of us with interest but limited time it’s helpful to see things posted in this fashion. It would be nice to see RealClimate address these concerns. No, I don’t expect that to happen.

I have just checked the page where the raw data is, and it’s interesting to see the timestamps involved with the different objects on the page. It seems to have happened on Sep, 8th. But what intrigues me Steve is the TayBavRing.raw file; it also seems to be new. Might it also represent something special?

I have checked the page where the raw data is, and it’s interesting to see the timestamps involved with the different objects on the page. It seems to have happened on Sep, 8th. But what intrigues me Steve is the TayBavRing.raw file; it also seems to be new. Might it also represent something special?

Title: The Dendroclimatic Divergence Phenomenon: reassessment of causes and implications for climate reconstruction

Description: Palaeoclimate reconstructions extend our knowledge of how climate varied in times before expansive networks of measuring instruments became available. These reconstructions are founded on an understanding of theoretical and statistically-derived associations acquired by comparing the parallel behaviour of palaeoclimate proxies and measurements of varying climate. Inferences about variations in past climate, based on this understanding, necessarily assume that the associations we observe now hold true throughout the period for which reconstructions are made. This is the essence of the uniformitarian principle. In some northern areas of the world, recent observations of tree growth and measured temperature trends appear to have diverged in recent decades, the so called “divergence” phenomenon. There has been much speculation, and numerous theories proposed, to explain why the previous temperature sensitivity of tree growth in these areas is apparently breaking down. The existence of divergence casts doubt on the uniformitarian assumption that underpins a number of important tree-ring based (dendroclimatic) reconstructions. It suggests that the degree of warmth in certain periods in the past, particularly in medieval times, may be underestimated or at least subject to greater uncertainty than is currently accepted. The lack of a clear overview of this phenomenon and the lack of a generally accepted cause had led some to challenge the current scientific consensus, represented in the 2007 report of the IPCC on the likely unprecedented nature of late 20th century average hemispheric warmth when viewed in the context of proxy evidence (mostly from trees) for the last 1300 years. This project will seek to systematically reassess and quantify the evidence for divergence in many tree-ring data sets around the Northern Hemisphere. It will establish a much clearer understanding of the nature of the divergence phenomenon, characterising the spatial patterns and temporal evolution. Based on recent published and unpublished work by the proposers, it has become apparent that foremost amongst the possible explanations is the need to account for systematic bias potentially inherent in the methods used to build many tree-ring chronologies including many that are believed to exhibit this phenomenon. (my emphasis).

Cutting through the verbiage, do I read this correctly that Professor Briffa has actually secured funding for a project to investigate how his previous work might have been affected by systematic bias?? An impartial bystander might think he could have a vested interest in the outcome…

Re: mjt1st (#48),
Bridge too far.
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It’s not a “flawed premise”. Many species from many alpine & treeline sites have been shown to be (WEAKLY) sensitive to temperature. The correlations, though weak, are too widespread to be a product of random chance alone. The modern breakdown in sensitivity at these cold sites is real. Tree poulations fit into discrete categories of those that maintain sensitivity (positive responders) and those that are losing it (negative responders): the divergence among samples is real. Briffa’s research project on divergence is legitimate.
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California bcps and Yamal larch appear, to me, to be exhibiting a “loss of sensitivity” (statistical, not biological) due to some other biophysical process that has kicked in to cover up a weak response to modern warming. (Soil warming/permafrost melting are interesting hypotheses.) But this does not invalidate the premise that trees respond to changes in temperature. It simply argues that the nature of the response changes over time. What this would violate is the uniformitarian assumption of dendroclimatology. It does not invalidate dendroclimatology as a whole.
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To argue categorically that trees do not respond to temperature is denial.
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To argue that tree responses to temperature in the 20th century may be greatly exaggerated in some studies – and that this has important consequences for large-scale temperature reconstructions – is reasonable.
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Please try to be reasonable.

Bender, I wasn’t saying the flawed premises is whether trees are sensitive to temperature or dendroclimatology as a whole is flawed. Nor was I saying that researching the divergence problem is not worthwhile.

Take the following quote…

The existence of divergence casts doubt on the uniformitarian assumption that underpins a number of important tree-ring based (dendroclimatic) reconstructions.

Divergence does not necessarily refute uniformitarian assumptions, it may only mean that the way temperature sensitivity is determined is innacurate. In other words, trees are responding to temperature as they always do, the divergence is caused as other factors (such as what you suggested above) influence what is being measured and the methodology used to determine sensitivity does not account for it properly. The divergence problem casts doubt more on methodology to me than as stated above, unifomitarian assumptions. This tree didn’t grow the way I thought it would….is it because its sensitivity changed or because my methodology in determining how it should grow is wrong. Maybe this is just splitting hairs though.

Re: mjt1st (#57),
Splitting hairs, yes. But nevertheless true. By “uniformity” I meant to imply uniformity in external disturbances as well – which is, agreed, not usually how the dendros use the term. I appreciate the correction. Sometimes some hairs need to be split. My point stands that stationarity in noise structure is assumed in these models, and it may not hold.

My point stands that stationarity in noise structure is assumed in these models, and it may not hold.

Agreed 100% and more specifically there doesn’t seem to be a method to either eliminate or accept a series as valid based on that. I think that this is also the point that is missed by those who think that picking a series based on matching the modern temp record is valid.

So I understand the arguments about how the Yamal collapse can have an effect on all but two of the reconstructions on the sphaghetti graph. But, what I’m not seeing is the new graph. Is it not possible to redo those reconstructions with the yamal data removed? Do all of them incorporate the Yamal data? What of the borehole and glacier reconstructions?

Furthermore, does anyone else get the feeling that tree ring reconstructions are just useless, and as such what is being found here is simply “we don’t know” what temps were before they were being monitored?

That wouldn’t really say much about AGW in modern times. There is still ample evidence without pre 20th century data.

Is it not possible to redo those reconstructions with the yamal data removed?

If you had all the source data and code for each curve it would be relatively easy. Might take you a day or two. I doubt very much that all the methods behind all the curves have been conveyed in sufficient detail to permit replication. Let’s see, it took 10 years for a dozen cores from a single site. At this rate we should be there by … 5009.

…..California bcps and Yamal larch appear, to me, to be exhibiting a “loss of sensitivity” (statistical, not biological) due to some other biophysical process that has kicked in to cover up a weak response to modern warming. (Soil warming/permafrost melting are interesting hypotheses.) But this does not invalidate the premise that trees respond to changes in temperature. It simply argues that the nature of the response changes over time. What this would violate is the uniformitarian assumption of dendroclimatology. It does not invalidate dendroclimatology as a whole. So what is predicted for future climates based on current research?

If the uniformitarian assumption of dendroclimatology is invalidated, then at the least the CI’s for dendro work grow significantly…and it becomes a challenge even to determine how much they should grow.

Bender’s correct: we cannot simply dismiss dendroclimatology as a science. We can see that a lot of work is needed to tighten up our understanding and the basic assumptions made.

I don’t remember where, but IIRC there was previous CA work to produce a set of CI bands for dendro proxies. The ranges were huge.

“To argue categorically that trees do not respond to temperature is denial.”

No one is arguing that trees don’t respond to temperature. The question is, “which ones are responding correctly when”? The idea that the divergence problem is unique to the late 20th century is also a problem. How do we know that this same problem hasn’t appeared often in the past. What is the basis for claiming that the divergence is unusual? And why would we assume that the surface temperature record doesn’t play at least some part in the divergence.

I can point to hundreds of comments where dendroclimatology is dismissed on principle. Even the term “treemometer” – cute as it is – is rightly perceived by dendros as dismissive and derogatory.
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As for the rest of the comment: you are preaching to the choir, dude.

Excellent work digging. What patience! I have seen comments elsewhere suggesting that one would not need to use many, if any, data from trees in the current era, but I find that a troublesome concept. Living trees should help define if a relationship between ring data and temperatures (for that locality) are valid. But still one would need to use a reasonable number of trees to do so, a statistically robust sample, not just one or two handfuls. Yes? It would be like me as an engineer certifying that the structure I just designed and built with concrete is adequate for its purposes because one or a few specimens of the concrete tested within specifications (despite the hundreds of individual deliveries and placements).

I also express wonder at how Briffa, Mann, et al., failed to explain themselves. If they believe some of the trees sampled, or some of the series, are better/worse than the rest, and why the samples/series were mixed and matched as they were, then why not explain it up front? And, why obfuscate, delay (and delay and delay and …), use old data archive formats and so forth? They’ve made themselves look like, … well, like people out to promote a preconceived agenda, even if they didn’t have one. Very short-sighted.

Anyone who has been involved in technical and scientific disciplines knows (or should) that errors and mistakes in perception sneak into our best efforts. Sometimes we get too close to our own work; we become blinded by our thoughts, perceptions and biases. Becoming too close to our on-going work can be illustrated in the way typographical errors creep into a document under construction: we invariably look at it with the sense of what we know we intended to say, rather than what it actually does say. The trick is to be able to step back, sometimes with the help of others — the more independent the better — and look over the work in progress with a healthy self-critical eye. That, of course, does not apply when the construction is intended to deceive or cloud an issue…

Quick question: how come when we eliminate all proxies, and only use instrumental temperature records, we still get a cut-off hockey stick? Why all the quibbling over the shaft, when the blade shows the AGW phenomenon?

Jim Carson (07:55:14) :
Although I think Steve is the 21st-century equivalent of Norman Borlaug, he is notoriously inept at showing us the Big Picture before relentlessly hammering away at the details. He’s even managed to confuse Jennifer Marohasy, in addition to TomP.
It seems clear to me now [someone correct me if I’m wrong] that Steve’s hypothesis is that the Yamal data is BIASED. And to test his hypothesis, he REMOVED the data he suspected of bias. And for good and valid mathematical reasons, he substituted some data that was NOT suspected of bias.

Well let me correct you because I think you are absolutely wrong.

From my high school science I know that a Random Experiment, (which is based on statistical principles), is an experiment, that can be repeated numerous times under the same conditions. The outcome of an individual random experiment must be independent and identically distributed. It must in no way be affected by any previous outcome and cannot be predicted with certainty.

The analogy that you have given is erroneous.

In this case the experiment has already been conducted and the results (data) collected. (It does not have to be repeated as in your analogy). Now we have to see what the results indicate without prejudging the outcome.

In Briffa’s case the data was carefully selected to agree with a specific outcome, which goes against the grain of the scientific method and statistics.

The second graph indeed is the one that excludes the 12 cherry-picked Briffa Yamal trees and demonstrates the bias.

But the last graph that Steve gives is the one that contains all the data. That illustrates a graph that seems to correlate with modern temperature data, BUT gives a medieval warm period warmer than the present AND does not demonstrate a hockey-stick pattern to show stable temperatures in the past 2,000 years.

I’m a little confused. Is the “son of hockey stick” predominately or solely due to cherry picking the data, or due to the mathematical methods used to enhance the signal to noise ratio as explained by others, or both?

Something that everyone should take note of is that the failure of these proxy reconstruction efforts is not good news. The implications of AGW could be very serious and will require very important decisions that have very serious consequences if they fail. The failure of the proxy reconstruction science will mean that the decisions makes will face more uncertainty in making these decisions. This is not good news.

The work reported here is very important since it means the decision makers will not be relying on findings that are without merit. However it is unfortunate that the proxy reconstructions can not be made to work.

You have been a beacon of the scientific method in a sea of short cuts and shading the truth. I understand (but do not support) your efforts to keep this debate at a scientific level and not disparage without evidence.

But there comes a time when the scientific method needs to be saved from the charlatans and abusers. These people cherry picked data so they could consume vast amounts of research money. They have relegated themselves to holier than thou insights, discarding the scientific method and hiding data they knew to challenge their own Nobel Prize winning arguments.

They spread a cancer into the science you hold dear. Yet, you hold back and do not demand of them the same rigor you applied to their own dodgy claims. You need to understand that humanity, in all its glorious naiveté to science does want charismatic leaders with bold decision points clearly articulated.

The peer review process is dead and gone and useless. You have earned the right to shine a spotlight on this fact. You have fought those who abused it to push agendas and false results. It is time you supported a chorus of outrage at this fiction. We may not articulate the details well, but there are a lot of people simply angered over the duplicity, who need help articulating the dishonesty here.

My hat is off to you sir. I am late to this debate and stand in awe of your 9 years of beating your head against these false results. It has been a heroic effort.

Perhaps this is a little OT – but isn’t it the case that for AGW to be nasty, the amplifying “feedbacks”, (water vapour and others), have to kick in much as specified in those GCM models? Even a doubling of CO2 produces only about a 1-1.2 C temperature increase directly – which seems to be uncontroversial.

But if it was just as warm in the MWP, (and the Roman period, and the Holocene Optimun), then temperatures must have risen into those periods – to a similar extent as they have the past 150 years. If the “feedbacks” are real why didnt they kick in in the past? They seem to have had several good oppurtunities to do so.

It seems to me that the MWP et al, (if valid), are strong evidence, (not definitive, but fairly strong), that the “feedbacks” do not actually happen. Is that why the “Team” keeps making statistically desperate attempts to pump out one “hockey stick” after another??

Perhaps better informed people than me might like to comment on that?

(I am only an occasional visitor to CA but I also want to add my congratulations to Steve – he has been a great servant of science – whichever side is ultimately right).

OK, so I’m feeling stupid. Looking at the graph’s that Steve did using the ‘correct’ (non cherry picked data) the temperature reconstruction (shown in the graph in the UK Telegraph link) seems to be the same until the 20th century or so. The instrumented record then shows warming (yes I am aware of homogeneity problems). However, the black trace on the chart is almost the same as the alleged faulty reconstruction, but diverges in the 20th century (when it shows a marked downward trend) when even we skeptics agree that it has warmed notably. If anything this graph seems to indicate that medieval warm period was not warmer than the late 20th century and that rather something odd (or wrong) going on with the reconstructions for the medieval warm period, something odd seems to be going on with the reconstruction in the 20th century with the new analysis b/c the trend is opposite to that derived from the observed SAT record. These data seem to suggest that we have cooled in the last 100 or so years? What am I missing here? Perhaps it is the scale and units. Why not plot the “correct” temperature reconstruction using the same scale and units as what Mann et al. (and others) used? That would help us all place this new construction in context of previous proxy work and SAT observations since circa 1880. Thanks.

Re: Lorax (#76), Matt Buckels (#77),
While Steve has reproduced one of the temperature “hockey stick” reconstruction graphs in the first figure above, the rest of the graphs involved in this whole Briffa kerfuffle are NOT temperature reconstructions. They are unitless depictions of some of the data that gets folded into said reconstructions.

Those who claim disclosure of these errors provides definitive proof of anything about AGW are completely missing the point.

Matt, you are correct:

The point is that this kind of dendroclimatology research is subject to far more uncertainty than some scientists would have us believe. Unfortunately, these tree ring studies have proven incurably addictive to the most widely promoted (self-described “Hockey Team”) climate scientists.

It is quite possible to do better science than to use discredited data and invalid statistical analysis techniques. Sadly, the Team doesn’t like to go there. Here at CA we try hard to avoid imputing motives to such activity, even though the Team generates its own PR about motivation.

We try to stick to the science. And that’s why it is here you will find those who have created a temperature reconstruction that completely avoids tree ring studies. No, not Steve.

Search Climate Audit for Craig Loehle’s work (and the auditing of his work that took place here.) You’ll find good statistics, review by statisticians, and a reconstruction refreshingly free of tree rings.

My sadness is that Craig’s work is among the very few that aspires to a higher standard. If we remove studies that make use of tree rings from the first figure in the original post above, there’s not much to look at.

We all enjoy the nice line graphs. But perhaps other kinds of data would be more valuable for future analysis. I myself am curious about arctic treeline efforts.

Has anyone discovered a way to map historical arctic treeline trends in such a way that an historical temperature proxy can be produced?

If no one minds what may be a seemingly obvious question… As a non-skeptic, but generally a skeptical person, I must admit I find this very interesting. I have some very well qualified mates and about a year ago I ran a survey about climate change and certainly amongst those with genuine academic credentials there were some concerns raised about some of the statistical methods used in climate science…

But anyway that is beside the question, which is this:

While these Climate Audit findings are being used by many to discredit the hockey stick, lay the boot in to “the team” etc, is the key scientific conclusion that if a larger sample of trees gives a result that is in direct conflict with the known recent instrumental temperature record then in fact the whole concept of reconstructing temperatures using tree cores has to be questioned, and in fact the temperature reconstructions that appear in the first figure of this post that show that “today” is warmer than the past, are in fact not reliable temperature reconstructions?

Sorry if it sounds simple, but I’m just trying to be clear on the actual scientific ramifications rather than just the questions about the integrity of Biffra and other climate scientists.

is the key scientific conclusion … the temperature reconstructions that appear in the first figure of this post that show that “today” is warmer than the past, are in fact not reliable temperature reconstructions?

“I find it extremely objectionable that there was never any formal report on the Polar Urals Update. The Esper version here is the first direct evidence of Hockey Team knowledge of this. In speculative mining businesses, if you have new drill results that change the understanding of an ore body, you have to publish them. Why the hell didn’t Briffa have to publish the updated Polar Urals results, given the big splash that he’d made in Nature about the coldest year of the millennium? It was even mentioned in IPCC 1995.”

See Steve Mosher’s link in 23 above. We are all still waiting. Optimism can be an evanescent thing.

[…] I’ve observed on a number of occasions that the difference between Polar Urals and Yamal is, by itself, material to most of the non-bristlecone reconstructions that supposedly "support" the Hockey Stick. For example, in June 2006, I showed the direct impact of a simple sensitivity study using Polar Urals versus Yamal – an issue also recently discussed here. […]

[…] I’ve observed on a number of occasions that the difference between Polar Urals and Yamal is, by itself, material to most of the non-bristlecone reconstructions that supposedly “support” the Hockey Stick. For example, in June 2006, I showed the direct impact of a simple sensitivity study using Polar Urals versus Yamal – an issue also recently discussed here. […]

[…] hockey stick shape if a little data from the same area was added. This series has been used in a dozen reconstructions. Is it any surprise those reconstructions got the same result as Mann got? All this […]

[…] all of the supposedly “independent” IPCC multiproxy studies (see an October 2009 discussion here) and because it is particularly influential in contributing an HS-shape to the studies that do not […]

[…] In addition to investigating the causes of these extreme events, the multiple analyses of all of the events allowed the pseudoscientists to compare and contrast the strengths and weaknesses of their various methods of analysis. Despite the fact that they “just kinda made it up” as they went along, there was considerable agreement between the assessments of the same events because the results were provided to the teams in advance. Think GCM and spaghetti graph. […]